This invention relates to mat forming apparatus or generally to material handling apparatus.
There are various applications where various mat-forming materials, such as natural and man-made fibers, particles, granules, filaments, slivers, strands, flakes, and the like, are processed to form a mat which is then further processed to arrive at a desired product. Such products can be reconstituted fiberboard, reinforced plastics, other composite articles, or the like. Various arrangements have been proposed for building such mats, for example gravity feed of the materials into a suitable mold, die, or other holding device, and arrangements which add a vibratory mechanism to the gravity feed. Some of the problems encountered in such prior art arrangements are the materials are either entangled at the start or become entangled in the process, such that they are delivered to the die in clumps. Also, they may become undesirably stratified due to differences in specific gravity, size and geometry of different materials. In addition, they may have a moisture content which is too high and, therefore, must be separately dried before further processing.
By way of further explanation, if delivered in clumps, or undesirably stratified, the uniformity and structural characteristics of the final product is affected. As a specific prior art problem, mats can be processed to composite articles through a compaction step wherein the fibers, with suitable binders, are compressed under heat and pressure. Too high a moisture content in the mats can result in steam being generated in the compaction step which can interfere with the compaction step and/or adversely affect the end product.
Among the objects of this invention is to provide a mat forming apparatus which provides generally uniform distribution of various materials or material mixes throughout the formed mat.
Another object of this invention is to provide a mat forming apparatus which inherently reduces the high moisture content of the materials being used to form the mat and which lends itself well to additional moisture removal.
A more general object of this invention is to provide apparatus capable of breaking up entangled materials and/or drying such materials as desired.
For the achievement of these and other objects, this invention proposes having a hollow material transporting member and drive means for producing a pressure differential across spaced portions of the transporting member so that materials are propelled from one spaced portion to the other within the hollow transporting member. Material directing means is also provided which communicates with the drive means for receiving materials from the hollow transporting means and, responsive to the drive means, is operative to direct received materials in a predetermined path. The hollow transporting member has a non-linear inner surface so that flow therethrough is turbulent causing materials being transported therein to experience turbulent flow in traveling from one spaced portion to the other. The apparatus may also include an arrangement associated with said material directing means for receiving the materials and confining received materials in a defined space.
Preferably, mat forming apparatus is made up of a blower and an elongated, hollow corrugated hose or tube, one end of which is open and the other end of which is attached to the inlet end of the blower so that the blower produces a pressure differential across the ends of the corrugated tube and the materials are propelled from the open end of the corrugated tube to the other end. A hollow, generally flexible or rigid, but swingable, tubular member has one end connected to the outlet of the blower and its other end freely movable and operative to direct received materials in a predetermined path or direction. The corrugated tube defines a non-linear inner surface so that flow in the corrugated tube is turbulent and causes materials to experience turbulent flow in being propelled from the open end to the blower. The arrangement also includes a frame associated with the hollow, flexible member for receiving and confining received materials in a defined space.
Preferably, the drive is a centrifugal blower and the materials are transported through the blower where they are further separated or mixed. Also, the apparatus includes a member having an interstitial construction such as a screen extending across the lower end of the frame to provide, at that point, a generally open construction permeable to air while preventing the passage therethrough of materials so that materials are accumulated in the frame. It is also contemplated that an exhaust arrangement will be associated with the frame to receive air passing through the frame, the exhaust mechanism itself being covered by the same type of member extending over the lower end of the frame and through which air must pass and against which the materials are directed. Means can also be included for withdrawing air from the interior of the exhaust mechanism to thereby enhance the overall flow of air through the apparatus while further augmenting the collection of the material in the formation of the mat.